Re: tipc_init(), WARNING: at arch/x86/mm/highmem_32.c:52, [2.6.24-rc4-git5: Reported regressions from 2.6.23]

Matt Mackall
2007-12-08T19:01:18Z

On Sat, Dec 08, 2007 at 09:54:06AM -0800, Linus Torvalds wrote:
>
>
> On Sat, 8 Dec 2007, Linus Torvalds wrote:
> >
> > But I'll apply it anyway, because it looks "obviously correct" from the
> > standpoint that the _other_??slob user already clears the end result
> > explicitly later on, and we simply should never pass down __GFP_ZERO to
> > the actual page allocator.
>
> Actually, I take that back. The other slob users are different. They share
> pages, this codepath does not.
>
> So I think a more proper solution would be:
> (a) Something like this patch (which includes my previous mm/slub.c
> change)
> (b) don't warn about atomic GFP_ZERO's - unless they have GFP_HIGHMEM set
> *too*.
>
> So which warning is it that triggers the bogus error?

While I think the whole GFP_ZERO thing is a bit broken here, this is
an improvement on my original patch, so:

Acked-by: Matt Mackall <mpm@selenic.com>
> ---
> mm/slob.c | 2 +-
> mm/slub.c | 3 +++
> 2 files changed, 4 insertions(+), 1 deletions(-)
>
> diff --git a/mm/slob.c b/mm/slob.c
> index ee2ef8a..773a7aa 100644
> --- a/mm/slob.c
> +++ b/mm/slob.c
> @@ -330,7 +330,7 @@ static void *slob_alloc(size_t size, gfp_t gfp, int align, int node)
>
> /* Not enough space: must allocate a new page */
> if (!b) {
> - b = slob_new_page(gfp, 0, node);
> + b = slob_new_page(gfp & ~__GFP_ZERO, 0, node);
> if (!b)
> return 0;
> sp = (struct slob_page *)virt_to_page(b);
> diff --git a/mm/slub.c b/mm/slub.c
> index b9f37cb..9c1d9f3 100644
> --- a/mm/slub.c
> +++ b/mm/slub.c
> @@ -1468,6 +1468,9 @@ static void *__slab_alloc(struct kmem_cache *s,
> void **object;
> struct page *new;
>
> + /* We handle __GFP_ZERO in the caller */
> + gfpflags &= ~__GFP_ZERO;
> +
> if (!c->page)
> goto new_slab;

--
Mathematics is the supreme nostalgia of our time.